1. Technical Field of the Invention
The present invention relates in general to the wireless communications field and, in particular, to an improved method for monitoring authentication performance in wireless communication networks.
2. Description of Related Art
The Global Challenge (GC) authentication procedure currently used in Time Division Multiple Access/Frequency Division Multiple Access (TDMA/FDMA) mobile communication systems allows a network operator to validate on the control channel, mobile subscribers' access requests to the network. Each subscriber maintains a unique set of secret authentication keys (i.e., Shared Secret Data or SSD information). This SSD information is used in certain calculations for the authentication procedure. The subscribers' Home Location Register (HLR) also maintains a copy of the subscribers' secret authentication keys.
The way most operators have implemented their existing TDMA/FDMA mobile networks, the Mobile Services Switching Center/Visitor Location Register (MSC/VLR) also maintains a copy of the subscribers' secret authentication keys or SSD information. The main purpose for maintaining the subscriber SSD information in an MSC/VLR is to avoid ANSI-41 message signalling congestion on the transmission link or interface between the MSC and HLR (Reference Point C as defined in the TIA/EIA-41 protocol).
There are a number of different settings needed to ensure that network subscribers are being globally challenged. Examples of these settings are cell indicators and the different access types which are to be globally challenged.
A significant problem with the GC authentication procedures used in existing TDMA/FDMA mobile systems is related to the use of these procedures by an external operator (i.e., an operator for a different network's service provider). For example, if a home network's MSC/VLR maintains a copy (which is done in most networks) of a subscriber's SSD information to be used for authentication purposes, the only ANSI-41 message signalling (apart from an initial access request) conveyed outside the MSC for the GC operation is an Authentication Failure report. This report is generated when a network determines that a fraudulent access request has been made. Conversely, if a network does not determine that a fraudulent access request has been made, then there is no GC-related report generated by the network that would allow an external operator to determine whether or not that network's GC function is still active and configured correctly. In other words, for existing TDMA/FDMA mobile networks, an external operator has no proof that another service provider's network (e.g., cooperating in accordance with a valid roaming agreement) has an active GC function. This problem is particularly significant for an external operator of a network having a plurality of roaming agreements with other networks, because the external operator needs assurance that its subscribers are being globally challenged as they roam.
The existing approaches used by network operators to extract authentication information from an MSC are typically proprietary. For example, one application, MDATA, is a proprietary application developed and used by the Ericsson Corporation to extract subscriber authentication information and results from an Ericsson MSC. This approach solves the above-described GC authentication problem to a great extent for Ericsson. However, a significant problem with this and similar proprietary approaches is that an external operator is unable to access the application directly in order to extract subscriber authentication results from the MSC where the MS is registered. Additionally, the proprietary authentication applications being used typically do not provide access to data across networks (i.e., no inter-network data transfers are performed). Notably, at present, there are no standardized solutions for reporting a successful GC, neither within one's own network nor to an external network. Nevertheless, as described in detail below, the present invention successfully solves the above-described problems and other related problems.